2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
6 * Ethernet-type device handling.
8 * Version: @(#)eth.c 1.0.7 05/25/93
11 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
12 * Mark Evans, <evansmp@uhura.aston.ac.uk>
13 * Florian La Roche, <rzsfl@rz.uni-sb.de>
14 * Alan Cox, <gw4pts@gw4pts.ampr.org>
17 * Mr Linux : Arp problems
18 * Alan Cox : Generic queue tidyup (very tiny here)
19 * Alan Cox : eth_header ntohs should be htons
20 * Alan Cox : eth_rebuild_header missing an htons and
22 * Tegge : Arp bug fixes.
23 * Florian : Removed many unnecessary functions, code cleanup
24 * and changes for new arp and skbuff.
25 * Alan Cox : Redid header building to reflect new format.
26 * Alan Cox : ARP only when compiled with CONFIG_INET
27 * Greg Page : 802.2 and SNAP stuff.
28 * Alan Cox : MAC layer pointers/new format.
29 * Paul Gortmaker : eth_copy_and_sum shouldn't csum padding.
30 * Alan Cox : Protect against forwarding explosions with
31 * older network drivers and IFF_ALLMULTI.
32 * Christer Weinigel : Better rebuild header message.
33 * Andrew Morton : 26Feb01: kill ether_setup() - use netdev_boot_setup().
35 * This program is free software; you can redistribute it and/or
36 * modify it under the terms of the GNU General Public License
37 * as published by the Free Software Foundation; either version
38 * 2 of the License, or (at your option) any later version.
40 #include <linux/module.h>
41 #include <linux/types.h>
42 #include <linux/kernel.h>
43 #include <linux/sched.h>
44 #include <linux/string.h>
46 #include <linux/socket.h>
48 #include <linux/inet.h>
50 #include <linux/netdevice.h>
51 #include <linux/etherdevice.h>
52 #include <linux/skbuff.h>
53 #include <linux/errno.h>
54 #include <linux/config.h>
55 #include <linux/init.h>
61 #include <asm/uaccess.h>
62 #include <asm/system.h>
63 #include <asm/checksum.h>
65 __setup("ether=", netdev_boot_setup
);
68 * Create the Ethernet MAC header for an arbitrary protocol layer
70 * saddr=NULL means use device source address
71 * daddr=NULL means leave destination address (eg unresolved arp)
74 int eth_header(struct sk_buff
*skb
, struct net_device
*dev
, unsigned short type
,
75 void *daddr
, void *saddr
, unsigned len
)
77 struct ethhdr
*eth
= (struct ethhdr
*)skb_push(skb
,ETH_HLEN
);
80 * Set the protocol type. For a packet of type ETH_P_802_3 we put the length
81 * in here instead. It is up to the 802.2 layer to carry protocol information.
85 eth
->h_proto
= htons(type
);
87 eth
->h_proto
= htons(len
);
90 * Set the source hardware address.
94 saddr
= dev
->dev_addr
;
95 memcpy(eth
->h_source
,saddr
,dev
->addr_len
);
98 * Anyway, the loopback-device should never use this function...
101 if (dev
->flags
& (IFF_LOOPBACK
|IFF_NOARP
))
103 memset(eth
->h_dest
, 0, dev
->addr_len
);
109 memcpy(eth
->h_dest
,daddr
,dev
->addr_len
);
118 * Rebuild the Ethernet MAC header. This is called after an ARP
119 * (or in future other address resolution) has completed on this
120 * sk_buff. We now let ARP fill in the other fields.
122 * This routine CANNOT use cached dst->neigh!
123 * Really, it is used only when dst->neigh is wrong.
126 int eth_rebuild_header(struct sk_buff
*skb
)
128 struct ethhdr
*eth
= (struct ethhdr
*)skb
->data
;
129 struct net_device
*dev
= skb
->dev
;
131 switch (eth
->h_proto
)
134 case __constant_htons(ETH_P_IP
):
135 return arp_find(eth
->h_dest
, skb
);
139 "%s: unable to resolve type %X addresses.\n",
140 dev
->name
, (int)eth
->h_proto
);
142 memcpy(eth
->h_source
, dev
->dev_addr
, dev
->addr_len
);
149 static inline unsigned int compare_eth_addr(const unsigned char *__a
, const unsigned char *__b
)
151 const unsigned short *dest
= (unsigned short *) __a
;
152 const unsigned short *devaddr
= (unsigned short *) __b
;
155 BUILD_BUG_ON(ETH_ALEN
!= 6);
156 res
= ((dest
[0] ^ devaddr
[0]) |
157 (dest
[1] ^ devaddr
[1]) |
158 (dest
[2] ^ devaddr
[2])) != 0;
164 * Determine the packet's protocol ID. The rule here is that we
165 * assume 802.3 if the type field is short enough to be a length.
166 * This is normal practice and works for any 'now in use' protocol.
169 __be16
eth_type_trans(struct sk_buff
*skb
, struct net_device
*dev
)
174 skb
->mac
.raw
= skb
->data
;
175 skb_pull(skb
,ETH_HLEN
);
178 if (*eth
->h_dest
&1) {
179 if (!compare_eth_addr(eth
->h_dest
, dev
->broadcast
))
180 skb
->pkt_type
= PACKET_BROADCAST
;
182 skb
->pkt_type
= PACKET_MULTICAST
;
186 * This ALLMULTI check should be redundant by 1.4
187 * so don't forget to remove it.
189 * Seems, you forgot to remove it. All silly devices
190 * seems to set IFF_PROMISC.
193 else if(1 /*dev->flags&IFF_PROMISC*/) {
194 if (unlikely(compare_eth_addr(eth
->h_dest
, dev
->dev_addr
)))
195 skb
->pkt_type
= PACKET_OTHERHOST
;
198 if (ntohs(eth
->h_proto
) >= 1536)
204 * This is a magic hack to spot IPX packets. Older Novell breaks
205 * the protocol design and runs IPX over 802.3 without an 802.2 LLC
206 * layer. We look for FFFF which isn't a used 802.2 SSAP/DSAP. This
207 * won't work for fault tolerant netware but does for the rest.
209 if (*(unsigned short *)rawp
== 0xFFFF)
210 return htons(ETH_P_802_3
);
215 return htons(ETH_P_802_2
);
218 static int eth_header_parse(struct sk_buff
*skb
, unsigned char *haddr
)
220 struct ethhdr
*eth
= eth_hdr(skb
);
221 memcpy(haddr
, eth
->h_source
, ETH_ALEN
);
225 int eth_header_cache(struct neighbour
*neigh
, struct hh_cache
*hh
)
227 unsigned short type
= hh
->hh_type
;
229 struct net_device
*dev
= neigh
->dev
;
231 eth
= (struct ethhdr
*)
232 (((u8
*)hh
->hh_data
) + (HH_DATA_OFF(sizeof(*eth
))));
234 if (type
== __constant_htons(ETH_P_802_3
))
238 memcpy(eth
->h_source
, dev
->dev_addr
, dev
->addr_len
);
239 memcpy(eth
->h_dest
, neigh
->ha
, dev
->addr_len
);
240 hh
->hh_len
= ETH_HLEN
;
245 * Called by Address Resolution module to notify changes in address.
248 void eth_header_cache_update(struct hh_cache
*hh
, struct net_device
*dev
, unsigned char * haddr
)
250 memcpy(((u8
*)hh
->hh_data
) + HH_DATA_OFF(sizeof(struct ethhdr
)),
251 haddr
, dev
->addr_len
);
254 EXPORT_SYMBOL(eth_type_trans
);
256 static int eth_mac_addr(struct net_device
*dev
, void *p
)
258 struct sockaddr
*addr
=p
;
259 if (netif_running(dev
))
261 memcpy(dev
->dev_addr
, addr
->sa_data
,dev
->addr_len
);
265 static int eth_change_mtu(struct net_device
*dev
, int new_mtu
)
267 if ((new_mtu
< 68) || (new_mtu
> 1500))
274 * Fill in the fields of the device structure with ethernet-generic values.
276 void ether_setup(struct net_device
*dev
)
278 dev
->change_mtu
= eth_change_mtu
;
279 dev
->hard_header
= eth_header
;
280 dev
->rebuild_header
= eth_rebuild_header
;
281 dev
->set_mac_address
= eth_mac_addr
;
282 dev
->hard_header_cache
= eth_header_cache
;
283 dev
->header_cache_update
= eth_header_cache_update
;
284 dev
->hard_header_parse
= eth_header_parse
;
286 dev
->type
= ARPHRD_ETHER
;
287 dev
->hard_header_len
= ETH_HLEN
;
288 dev
->mtu
= 1500; /* eth_mtu */
289 dev
->addr_len
= ETH_ALEN
;
290 dev
->tx_queue_len
= 1000; /* Ethernet wants good queues */
291 dev
->flags
= IFF_BROADCAST
|IFF_MULTICAST
;
293 memset(dev
->broadcast
,0xFF, ETH_ALEN
);
296 EXPORT_SYMBOL(ether_setup
);
299 * alloc_etherdev - Allocates and sets up an ethernet device
300 * @sizeof_priv: Size of additional driver-private structure to be allocated
301 * for this ethernet device
303 * Fill in the fields of the device structure with ethernet-generic
304 * values. Basically does everything except registering the device.
306 * Constructs a new net device, complete with a private data area of
307 * size @sizeof_priv. A 32-byte (not bit) alignment is enforced for
308 * this private data area.
311 struct net_device
*alloc_etherdev(int sizeof_priv
)
313 return alloc_netdev(sizeof_priv
, "eth%d", ether_setup
);
315 EXPORT_SYMBOL(alloc_etherdev
);